These words refer to a person who steals property that rightfully belongs to others. Thief is the most general, since it can refer to any such action regardless of the means used: the thief who had broken into the house during their absence; the thief who had seized her purse and darted into the milling crowd. At its most specific, thief might most often suggest someone who takes property by stealth, rather than by a direct confrontation with the owner. Robber may be used in as general a way as thief , but because it relates closely to the legally defined crime of robbery, it may suggest a direct confrontation in which the victim is forced to surrender this valuables by the use or threat of violence: fearing that he might be accosted by a robber if he walked through the dark, deserted part. A burglar is one who breaks into a house at night to loot it, usually with the intention of avoiding a confrontation with those living there.

Brigand and pirate refer to members of organized bands that are devoted to robbery and live outside the law. Brigand would be typically applied to thieves whose sphere of operations is a rural area and who terrorize the surrounding countryside; pirates are historically represented as having fast ocean-going ships to run down and loot other ships on the high seas. Gangster is the equivalent term for the member of a modern-day organized group of people based mostly in cities and set up to make money by all kinds of illegal activities.

Bandit is the most vague of these words; it is now less used as a generic term, but is sometimes used interchangeably with brigand , suggesting an organized group in a rural setting, such as bushrangers in 19th-century Australia. It may also be used of a lone marauder or robber , with the same sort of rural setting implied. In this case, theft by the use of threat or violence is suggested. The bandit in a typical Western movie, for example, rides a horse and goes armed, either alone or in a group.